Non-volatile storage devices include flash memory devices and other storage devices. In a flash memory device, a storage element may be programmed to store a particular threshold voltage that indicates one or more bit values. For example, a particular range of threshold voltages may correspond to a logic “1” bit value, and another range of threshold voltages may correspond to a logic “0” bit value.
Non-volatile storage devices may use error correction techniques to improve reliability of data storage and retrieval. For example, data may be encoded prior to being stored at a storage device, and the data may be decoded after being read from the storage device to correct one or more errors in the data (up to an error correction capability, such as a probabilistic error correction capability).
Certain error correction techniques use soft bits to improve the error correction capability. A soft bit may indicate a reliability of a hard bit read from a storage element. As an example, a hard bit may indicate a logic “0” bit value, and a soft bit corresponding to the hard bit may indicate that the logic “0” bit value is relatively reliable (e.g., if a read voltage that reflects a state of a storage element is relatively far from the read threshold) or that the logic “0” bit value is relatively unreliable (e.g., if the read voltage indicating the state of the storage element is adjacent to a boundary of the target range of threshold voltages). Soft bits may improve a decoding process by indicating which bits of data are likely to be “incorrect” (e.g., due to being near a boundary of a threshold voltage range).
Generating and using soft bits consumes resources at a storage device. For example, additional sensing operations may be performed to generate soft bits (as compared to generating only hard bits during a read process). As another example, transferring soft bits from a memory to a controller may use system bandwidth and may reduce resources available for other operations, which may slow performance of the memory in some cases.